1. Field of the Invention
The present invention relates to an endoscope apparatus in which the shape of endoscope insertion portion can be confirmed.
2. Description of the Related Art
Endoscopes have recently come into wide use in the fields of medical treatment and industry. In endoscopes with a flexible insertion portion, this insertion portion can be inserted into curved body cavities. Inserting the insertion portion into a body cavity makes it possible to conduct diagnostics of organs on the deep part of the body cavity, without surgery, or to conduct, if necessary, the treatment such as removal of polyps by passing a treatment tool through a passage channel of the endoscope.
However, when examination inside the colon is conducted by passing an endoscope with an elongated endoscope, for example, through the anus, certain skills are required for smoothly inserting the insertion portion into the curved body cavity. This is because, the shape of the inserted portion of the endoscope, for example, the distal end of the endoscope inside the body cavity, cannot be determined.
In order to make it possible to determine the shape of the inserted portion of the endoscope, a section which is not transparent to X rays can be provided on the insertion portion, this section allowing the insertion shape of the endoscope to be grasped by irradiating X ray. In other words, the detection of the distal end position or curved shape of the insertion portion inside a body cavity can be detected by irradiating the body with X rays.
However, endoscope shape detectors using X rays have a large size, and sufficiently large examination rooms are required to accommodate such devices. Furthermore, during endoscopic examination, the operator has to conduct the operation of X ray irradiation in addition to the endoscope operation. As a result, the burden on the operator is increased. Furthermore, frequent irradiation with X rays increases the radiation dose and can be dangerous for both the patient and the operator. With the foregoing in view, detecting the shape of the insertion portion of the endoscope by using X rays is not necessarily the desirable method.
For this reason, an insertion portion shape detection device has been suggested in which an insertion shape detection probe provided, for example, with a plurality of magnetic field detection elements, and a magnetic field detector are used, the insertion shape detection probe is passed into and arranged in a passage channel provided in the endoscope, signals from the magnetic field detection elements are received by the detection device arranged outside, and the shape of the inserted portion of the endoscope is displayed on the screen of the detection device.
However, in order to detect accurately the shape of the insertion portion by passing and arranging the insertion shape detection probe in the treatment tool passage channel, a small-diameter insertion shape detection probe has to be formed and a plurality of elements and signal lines extending from those elements have to be arranged in the insertion shape detection probe.
In the conventional process for forming the insertion shape detection probe, a plurality of elements and signal lines are arranged inside a tube and then the inside of the tube is filled, for example, with silicon as a solvent. Accordingly, the manufacturing process is difficult and time consuming. Moreover, unfavorable effects such as nonuniform arrangement of signal lines during filling with the solvent could be a problem.
When a shape detection probe with desired specifications could not be manufactured because of nonuniform arrangement of signal lines and a curving or twisting operation is conducted with such an insertion shape detection probe arranged in the treatment tool passage channel, the signal lines located inside the tube could be stretched and ruptured.
Furthermore, the insertion shape detection probe is not fixed with respect to the treatment tool passage channel. As a result, movement of the insertion shape detection probe inside the treatment tool passage channel could make impossible the accurate detection of the insertion portion shape. Moreover, when the operation of twisting the insertion portion or bending the curved section is conducted, there is a risk of the insertion shape detection probe protruding from the distal end surface of the endoscope. Accordingly, the insertion procedure is implemented by moving the distal end of the insertion shape detection probe to the operating end by a prescribed distance from the prescribed position inside the treatment tool passage channel and preventing the protrusion thereof. For this reason, too, there is a possibility that accurate detection of the insertion portion shape could not be conducted.